Microsoft's JavaScript strategy hurting IE 8?

Microsoft's focus on selected improvements in Internet Explorer's handling of Javascript has cost its latest browser in the race against competitors.

Internet Explorer 8 is ninth in a list of 10 browsers that have been tested for speed, with the previous version of Microsoft's browser - IE 7 - coming last. This list arrives from 3D-graphics specialist Futuremark.

The duo went up against a familiar field that included the latest available editions (some still in beta) of Apple's Safari, Google's Chrome, Firefox, and Opera.

Top of the table was Safari 4.0, with the Chrome 2.0.172.23 beta and Chrome 1.0.154.65 coming second and third respectively. The closest Firefox, which has been growing steadily and taking market share from IE, came to the top was version 3.5b4 beta.

The figures follow Microsoft's own attempts to sell the recently released IE 8 on the basis of its speed. A company video released in March claimed IE8 was three times as fast as Firefox when it came to loading web pages and one third quicker than Chrome.

Microsoft's competitors have been slowly cranking the performance of Javascript in their browsers. Safari 4.0 is expected to include the SquirrelFish Extreme Javascript engine. Chrome features Google's V8 open-source engine written in C++. And Firefox employs TraceMonkey, which uses tracing optimization and Adobe Systems' nanojit to boost SpiderMonkey.

But Microsoft has taken a different route on Javascript, arguing this is responsible for just 20 per cent of a web page's load time. So, instead of boosting IE 8's Javascript engine to keep up, Microsoft has optimized the browser as a whole for the most common user scenarios.

According to the IE 8 team that involved tuning JScript - Microsoft's implementation of the ECMAscript language - for faster string, array, and lookups. Also, there were changes to the core architecture to reduce the cost of functions calls, the creation of objects, and lookup patterns.

Microsoft has explained the changes in terms of making the user more productive.

Futuremark results are based on 400,000 users of its new Peacekeeper service designed to measure a browser's JavaScript performance. Peacekeeper bases its scores on operations per second or rendered frames per second depending on the test, the company said. ®